This is just me, but back when I did Karate, I hated fighting girls. They always had the advantage, because like a stupid gentlemen, I'd go easy on them cause they're girls.
I mean, I kicked a dude in the face and made him cry and knocked his teeth lose, but that was like, "Hey, suck it up", I kicked a girl a little too hard and it was like, "Holy fuck, what have I done, I'm a monster"

In fact, I one time punched this girl in the stomach for talking shit to me. I felt bad about it. And she was [someone I had no respect for]. And I still feel bad for hitting, her even though I barely regard her a person?
Cause she was a girl... that's why. Without those XX chromosomes, I'd have felt 0 guilt. Unless someone informed me that she was a boy who had a sex change, then I have to feel bad, even though it was her fault she got hit.

Do you think this is just societal programming or a natural sense of protectiveness that men have for women.

I had the same psychological resistance against hitting girls back during my early days of training. My instructor conditioned that out of me by making me fight girls who were black belts or otherwise more advanced than me at the time. This made me realize that he was right. When it comes to self-defense, your priority is....well...defending yourself or those you love. It's either your attacker or you/your loved one. It hardly matters who your opponent is when there's a possibility of serious injury or death.

I've been hooked in the head, blasted in the chest, choked out, completely outclassed by an opponent who was just way better than me with the same weapon I was using. Going through this teaches you things. I'm not a particularly big guy in the first place. I can't afford to go easy on anyone. I'm 5'9" or 5'10" and I was only 130 pounds back then. I was quick and I fought well but I hesitated in certain situations, and my sensei did a good job dealing with that. It's not an issue of pride or honor. It's an issue of survival.

When you are in a dangerous situation and escape is impractical or impossible, you can't afford to show your opponent any mercy. You can't hesitate to take full advantage of any openings and you should attack until your opponent can no longer threaten you. This means striking with full force at the most vulnerable targets, being completely serious from the beginning, and taking advantage of your surroundings as best as you can. No guilt now.

However, this also means that I understand how serious a self-defense situation is. Sparring is fun but a real fight is serious stuff. Anger has to be controlled. Therefore, I won't start needless fights or hurt people without a very good reason. I won't raise a hand against someone to hurt them if I'm not trying to REALLY hurt them. I'd feel bad about injuring anyone if I didn't really need to.

Oh man... the feeling of punching someone or something is just pure ecstasy for me... When I was like 5, I used to get picked on, until I jumped on the kids back and punching him repeatedly... all he did was lightly kick me on the leg, but the months of bottled up rage made me react ridiculously.
Ever since then, I felt beating others up made me respected. I even had dreams of hitting people with a baseball bat. One time, I became cool and popular for hitting a guy, and the feeling of being accepted and having others call me tough and cool... it was amazing. They all thought I was some great fighter, I wasn't but still... people thought I was cool, people actually admired me. I'd never felt that.

This is just me, but back when I did Karate, I hated fighting girls. They always had the advantage, because like a stupid gentlemen, I'd go easy on them cause they're girls.
I mean, I kicked a dude in the face and made him cry and knocked his teeth lose, but that was like, "Hey, suck it up", I kicked a girl a little too hard and it was like, "Holy fuck, what have I done, I'm a monster"

In fact, I one time punched this girl in the stomach for talking shit to me. I felt bad about it. [offensive passage removed] And I still feel bad for hitting, her even though I barely regard her a person?
Cause she was a girl ... that's why. Without those XX chromosomes, I'd have felt 0 guilt. Unless someone informed me that she was a boy who had a sex change, then I have to feel bad, even though it was her fault she got hit.

Do you think this is just societal programming or a natural sense of protectiveness that men have for women.

I'd feel bad about hitting anybody, but in this context...

I think it's more about hitting anybody who is physically weaker than you, really. Girls, typically, aren't as strong as guys because of simple biology, and that can't be helped. It's not a matter of sexism: our bodies were just built differently and there are things physically that girls can handle that men can't (i.e. flexibility)

This isn't always true, however: if a heavyweight boxing champion, who happens to be female, were to confront me in a fight, I wouldn't feel bad at all because 1) it's a proper fight and 2) I'd be running the other direction since she'd serve my ass on a silver platter no question. This goes for any girl whose physically stronger or really just fitter than me, and considering I watch anime, there are a fair amount of girls this applies to (even though I'm not in bad shape at all). If they are stronger than me, then giving me all is only fair, right?

I also took martial arts too, so this is true of any girl with a higher belt level as well (assuming they are of similar age) since my form is all about redirection, meaning even smaller opponents, with the right training, can take down even the biggest of guys if you redirect their energy correctly.

Edit:
You should feel bad for hitting anyone.
Especially if they didn't hit you first or even did anything to you.
Any sort of hitting should be the last thing to do. Did you even tell the girl to stop? I'd say no matter who you're with, just try to avoid any sort of violence. If you felt bad, an apology might help.
If i hit people is if they constantly do things I don't like or want them to do. Like someone forcing themselves on me.

Not really. If you give me enough reason to swing, your sex isn't going to save you from me. If you want to dish it out, be ready to take it as well. The idea that a woman (or man really) can assault someone and not expect retaliation based on their sex alone is laughable at best.

I mean come on...you want equality right? You get everything that goes with it.

I wouldn't hit her, but I would call her out. If she did hit me first, with no intention of stopping, I would.

For some reason, I feel like this would give the vibe that this would give a misunderstanding so just to clear it, I only punch guys, and if necessary, slap a girl, not punch. I just feel like punching would be a little too much, unless of course, they threw one at me first.